How does the loop of Henle enable the mammalian kidney to produce hyperosmotic urine?
I-The ascending limb of the loop actively extrudes Na+.
II-The descending limb interacts with the ascending limb to raise the concentration of the extracellular fluid in the renal medulla.
III-The concentration is further enhanced by the presence of urea,which draws water out of the collecting ducts by osmosis.
A)just I
B)II and III
C)just III
D)I and II
E)I,II,and III

Question

Quizplus · Accepted Answer

The loop of Henle plays a crucial role in the production of hyperosmotic urine by the mammalian kidney. The loop consists of two limbs - the descending and ascending limbs. The descending limb is permeable to water but not solutes, while the ascending limb is impermeable to water but actively extrudes Na+ from the lumen of the nephron. This creates a concentration gradient that raises the concentration of the extracellular fluid in the renal medulla. The concentration gradient is then further enhanced by the presence of urea, which is reabsorbed by the collecting ducts and recycled back into the medulla. Urea draws water out of the collecting ducts by osmosis, further concentrating the urine. Therefore, all three statements are true and contribute to the ability of the mammalian kidney to produce hyperosmotic urine.

How Does the Loop of Henle Enable the Mammalian Kidney